Little Alastair, Ma Shiyue, Haddleton David M, Tan Bowen, Sun Zhaoyang, Wan Chaoying
International Institute for Nanocomposites Manufacturing (IINM), WMG, University of Warwick, Coventry CV4 7AL, U.K.
Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.
ACS Omega. 2023 Oct 3;8(41):38658-38667. doi: 10.1021/acsomega.3c05932. eCollection 2023 Oct 17.
Poly(glycolic acid) (PGA) is a biodegradable polymer with high gas barrier properties, mechanical strength, and heat deflection temperature. However, PGA's brittleness severely limits its application in packaging, creating a need to develop PGA-based copolymers with improved elasticity that maintain its barrier properties and hydrolytic degradability. In this work, a series of PGBAT (poly(glycolic acid--butylene) adipate--butylene terephthalate) copolymers containing 21-92% glycolic acid () with values of 46,700-50,600 g mol were synthesized via melt polycondensation, and the effects of altering the on PGBAT's thermomechanical properties and hydrolysis rate were investigated. Poly(glycolic acid--butylene succinate) (PGBS) and poly(glycolic acid--butylene terephthalate) (PGBT) copolymers with high were synthesized for comparison. DSC analysis revealed that PGBAT21 ( = 21%) and PGBAT92 were semicrystalline, melting between 102.8 and 163.3 °C, while PGBAT44, PGBAT86-89, PGBT80, and PGBS90 were amorphous, with values from -19.0 to 23.7 °C. These high copolymers showed similar rates of hydrolysis to PGA, whereas those containing <50% GA showed almost no mass loss over the testing period. Their mechanical properties were highly dependent upon their crystallinity and improved significantly after annealing. Of the high copolymers, annealed PGBS90 ( 97,000 g mol) possessed excellent mechanical properties with a modulus of 588 MPa, tensile strength of 30.0 MPa, and elongation at break of 171%, a significant improvement on PGA's elongation at break of 3%. This work demonstrates the potential of enhancing PGA's flexibility by introducing minor amounts of low-cost diols and diacids into its synthesis.
聚乙醇酸（PGA）是一种具有高气体阻隔性能、机械强度和热变形温度的可生物降解聚合物。然而，PGA的脆性严重限制了其在包装领域的应用，因此需要开发具有改善弹性的基于PGA的共聚物，同时保持其阻隔性能和水解降解性。在这项工作中，通过熔融缩聚合成了一系列含有21%-92%乙醇酸（）且重均分子量为46,700-50,600 g/mol的聚（乙醇酸-丁二醇）己二酸酯-对苯二甲酸丁二醇酯（PGBAT）共聚物，并研究了改变乙醇酸含量对PGBAT热机械性能和水解速率的影响。合成了高乙醇酸含量的聚（乙醇酸-丁二醇琥珀酸酯）（PGBS）和聚（乙醇酸-丁二醇对苯二甲酸酯）（PGBT）共聚物用于比较。差示扫描量热法（DSC）分析表明，PGBAT21（=21%）和PGBAT92是半结晶的，熔点在102.8至163.3°C之间，而PGBAT44、PGBAT86-89、PGBT80和PGBS90是无定形的，玻璃化转变温度在-19.0至23.7°C之间。这些高乙醇酸含量的共聚物显示出与PGA相似的水解速率，而那些含有<50%乙醇酸的共聚物在测试期间几乎没有质量损失。它们的机械性能高度依赖于其结晶度，退火后显著改善。在高乙醇酸含量的共聚物中，退火后的PGBS90（重均分子量97,
